This invention relates generally to ankle braces and more particularly to ankle braces for applying a lifting force to selected portions of the foot.
Various ankle braces or supports have been disclosed in the patent literature for applying a lifting force to one or more portion of the foot for various reasons. Examples of such prior art patents are: U.S. Pat. Nos.: 4,494,534 (Hutson); 4,523,394 (Lindh et al.); 4,587,962 (Greene et al.); 4,753,229 (Sutherland); 5,016,623 (Krahenbuhl); 5,069,202 (Prock); 5,496,263 (Fuller II, et al.); 5,741,222 (Fiore); and 5,887,591 (Powell et al.).
It is well recognized among experts in podiatric and lower extremity biomechanics that the critical pivotal joint of the human foot is the talo-navicular joint. Previously, most foot orthotic interventions were designed to control the subtalar joint. Attempts to control the talo-navicular joint (medial flange, sustentaculum support) have caused potential irritation to this sensitive part of the human foot. Yet, recent experimental evidence, using arthrodesis procedures of cadaver models, have clearly shown that control of the talo-navicular joint will have profound control and limitation of the entire rearfoot complex, including the subtalar and calcaneal-cuboid joints.
To control the talo-navicular joint, a force, or moment must be applied medial to the axis of the entire rearfoot complex, which is slightly deviated in a more vertical alignment to the subtalar joint axis. To prevent plantar and medial migration of the head of the talus, the force must be applied in a dorsal, posterior and lateral direction which would cross almost perpendicular to the axis of rotation of the rearfoot complex. Heretofore no ankle brace has achieved that end.
In particular, the spring ligament complex of the human foot is the only structure that is anatomically designed to provide precise support of the talo-navicular joint. In severe foot pathologies such as the adult acquired flatfoot secondary to posterior tibial tendon dysfunction, the spring ligament complex becomes attenuated and the resultant foot deformity is uncontrolled with standard foot orthoses. Prior art in-shoe foot orthoses cannot apply significant moment of force in the proper direction to adequately control the talo-navicular joint.
This invention relates to an ankle brace comprising a stirrup or foot support, a lateral side limb member, a medial side limb member, and at least one lifting strap. The lateral side limb member is arranged for securement to the lateral side of a wearer""s leg. The medial side limb member is arranged for securement to the medial side of the wearer""s leg. The stirrup is arranged to receive the foot of the wearer and comprises a bottom plate having heel receiving end, a medial side, a contiguous medial arch area, a lateral side, a contiguous lateral arch area, a lateral sidewall projecting upward from the bottom plate on the lateral side adjacent the heel receiving end, and a medial sidewall projecting upward from the bottom plate on the medial side adjacent the heel receiving end. The lateral sidewall is pivotably connected to the lateral side limb member. The medial sidewall is pivotably connected to the medial side limb member.
In accordance with one aspect of this invention, the at least one lifting strap is a medial lifting strap that includes a first portion secured to the bottom plate at the arch area and projecting upward from the medial side of the bottom plate for extension over the foot of the wearer. The medial lifting strap also includes a second portion arranged for releasable securement to the lateral side limb member, whereupon when the second portion of the medial lifting strap is secured to the lateral side limb member the medial lifting strap applies a lifting force to the foot crossing perpendicularly to the axis of rotation of the foot""s subtalar joint and the foot""s rear foot complex joints.
In accordance with another aspect of this invention, the at least one lifting strap is a lateral lifting strap that includes a first portion secured to the bottom plate adjacent the lateral arch area and projecting upward from the lateral side of the bottom plate for extension over the foot of the wearer. The lateral lifting strap also includes a second portion arranged for releasable securement to the medial side limb member, whereupon when the second portion of the lateral lifting strap is secured to the medial side limb member the lateral lifting strap applies a lifting force to elevate the lateral longitudinal arch.
In accordance with still another aspect of this invention, the brace includes a first lifting strap and a lifting second strap. The first lifting strap is a medial lifting strap that includes a first portion secured to the bottom plate at the arch area and projecting upward from the medial side of the bottom plate for extension over the foot of the wearer. The medial lifting strap also includes a second portion arranged for releasable securement to the lateral side limb member, whereupon when the second portion of the medial lifting strap is secured to the lateral side limb member the medial lifting strap applies a lifting force to the foot crossing perpendicularly to the axis of rotation of the foot""s subtalar joint and the foot""s rear foot complex joints. The second lifting strap is a lateral lifting strap that includes a first portion secured to the bottom plate adjacent the lateral arch area and projecting upward from the lateral side of the bottom plate for extension over the foot of the wearer. The lateral lifting strap also includes a second portion arranged for releasable securement to the medial side limb member, whereupon when the second portion of the lateral lifting strap is secured to the medial side limb member the lateral lifting strap applies a lifting force to the foot to elevate the lateral longitudinal arch.
In accordance with another aspect of this invention the bottom plate of the ankle brace includes a medial recess located at the medial side in the arch area and/or a lateral recess located at the lateral side in the vicinity of the calcaneal cuboid joint area of the lateral arch. With respect to the medial recess a portion the first portion of the medial lifting strap is arranged to be located within the medial recess to apply the lifting force to the talo-navicular joint of the wearer""s foot. With respect to the lateral recess a portion the first portion of the lateral lifting strap is arranged to be located within the lateral recess to apply the lifting force to elevate the lateral longitudinal arch.